The present invention relates to adapters for pipes and, in particular, to a corrugated pipe adapter providing a smooth outside surface.
Various arrangements exist for connecting pipes to manholes in sewer systems. One such arrangement is disclosed in greater detail in U.S. Pat. No. 3,958,313, incorporated herein by reference. According to this arrangement, a flexible boot slips over the free end of the pipe and an external clamp compresses the boot onto the pipe to produce a boot-to-pipe seal. The other end of the boot is sealed within an aperture in a manhole riser. These boots can also be used to secure and seal pipes to other structures, such as other pipes.
Initially, these boots were used solely with smooth pipes (e.g., PVC pipes) or semi-smooth pipes (e.g., concrete pipes). A new type of pipe has been developed, however, having a corrugated outer surface, often called corrugated polyethylene. The corrugations or ribs on the outer surface of the pipes prevent the use of the standard booted connection. Thus, a need exists for an adapter that provides a smooth outer surface that can be used, for example, with the standard boots.
Some plastic and rubber adapters have been designed for joints between corrugated pipes, but these plastic and rubber adapters are typically not economical and are often difficult to install. One prior art corrugated pipe adapter 10 is shown in FIG. 1. This corrugated adapter 10 has a generally cylindrical configuration and includes an annular protuberance or rib 12 having a hollow cross section. The rib 12 fits tightly between the corrugations 22 on the corrugated pipe 20. Because of the tight fit and relatively stiff materials, however, this prior art corrugated pipe adapter 10 is difficult to install. Because of the hollow cross section, this prior art corrugated pipe adapter 10 is also difficult to splice. Furthermore, the dies needed to form the hollow cross section make the adapter more expensive.
Another type of adapter is shown in FIG. 2 and disclosed in U.S. Pat. No. 5,180,196, incorporated herein be reference. This adapter 14 is used with a ribbed conduit 15 known by the name Ultra-Rib. This adapter 14 has a solid cross section with a number of protuberances 16 extending between projecting ribs 18 on a length of the ribbed conduit 15. This adapter 14 is not designed, however, for use with polyethylene corrugated pipe. This adapter also must be installed by inverting the adapter and rolling the adapter into position (as shown in FIG. 2).
Accordingly, a need exists for a corrugated pipe adapter that is less expensive, easier to stretch and to place over the corrugated pipe, and easier to splice.
The present invention features a corrugated pipe adapter including a generally cylindrical sleeve having a generally smooth outer clamping surface and one or more protrusions extending from an inner surface of the sleeve. The corrugated pipe adapter preferably has a solid cross section, and each protrusion has side walls which preferably extend only partially into the groove between corrugations on the corrugated pipe. Each of the protrusions preferably has an arched geometry and sloping side walls.
The present invention also features a corrugated pipe adapter comprising a generally cylindrical sleeve having a generally smooth outer clamping surface and at least two partial protrusions extending from an inside of the generally cylindrical sleeve. The partial protrusions have at least two side walls adapted to be positioned on either side of a single corrugation of the corrugated pipe. The generally cylindrical sleeve can also have an inner sealing surface including one or more sealing elements protruding therefrom.
The present invention also features a system including the corrugated pipe adapter used in conjunction with a boot and a clamping mechanism whereby the clamping mechanism secures the boot against the generally smooth outer clamping surface of the corrugated pipe adapter. The pressure applied to the corrugated pipe adapter causes the side walls to move outwardly against the corrugations on the corrugated pipe.